Which method of fall ascertainment captures the most falls in prefrail and frail seniors?

There is no consensus on the most reliable method of ascertaining falls among the elderly. Therefore, we investigated which method captured the most falls among prefrail and frail seniors from 2 randomized controlled trials conducted in Zurich, Switzerland: an 18-month trial (2009–2010) including 200 community-dwelling prefrail seniors with a prior fall and a 12-month trial (2005–2008) including 173 frail seniors with acute hip fracture. Both trials included the same methods of fall ascertainment: monthly active asking, daily self-report diary entries, and a call-in hotline. We compared numbers of falls reported and estimated overall and positive percent agreement between methods. Prefrail seniors reported 499 falls (fall rate = 2.5/year) and frail seniors reported 205 falls (fall rate = 1.4/year). Most falls (81% of falls in prefrail seniors and 78% in frail seniors) were reported via active asking. Among prefrail seniors, diaries captured an additional 19% of falls, while the hotline added none. Among frail seniors, the hotline added 16% of falls, while diaries added 6%. The positive percent agreement between active asking and diary entries was 100% among prefrail seniors and 88% among frail seniors. While monthly active asking captures most falls in both groups, this method alone missed 19% of falls in prefrail seniors and 22% in frail seniors. Thus, a combination of active asking and diaries for prefrail seniors and a combination of active asking and a hotline for frail seniors is warranted.